The present invention relates generally to a measuring device for measuring anatomical features of a patient and, more specifically, the present invention relates to measuring a patient's hip, leg, or shoulder tilt with respect to one side versus the other to determine proper alignment and length, among others.
The human body has a symmetry that requires that each limb and the skeletal structure remain in proper alignment and substantially level as compared one side to the other. This symmetry leads to proper health and wellbeing. When dissymmetry occurs, such as when one limb is shorter than the other one, for example one leg being shorter than the other leg, poor health, pain and improper spinal curvatures as scoliosis can result. This dissymmetry also occurs when the hips through the pelvis are not level from side to side or when the shoulders are not level from side to side. In one study it was found that 11 percent of patients experiencing lower back pain were found to have a leg length discrepancy.
In order to identify the cause of this dissymmetry, different methods may be used. For example, one determines whether one leg is the same length as the other or whether the pelvis is properly horizontal, which in each case may be accomplished by taking measurements of the patient's body. In one method, the patient stands upright with the feet generally parallel to one another, slightly spaced apart, and the level of the iliac crests of the hips is determined. Boards are placed under the foot of the shorter limb until the pelvis of the patient becomes horizontal. If the lumbar tilt ceases when the iliac crests are rendered level, it is the result of one leg being shorter than the other.
If the patient experiences discomfort while standing, or on lumbar flexion or extension, the patient's shorter leg is raised by a platform under the patient's foot. If this eases or abolishes the patient's pain, the patient is then recommended to wear a raised heel indefinitely.
One problem with having the patient stand and then placing boards under the patient's foot is that it is still difficult to determine when the patient's pelvis becomes horizontal. This becomes a subjective observation by the individual conducting the exam and may not always accurately determine the amount of displacement that exists from one limb being shorter than the other limb or from the pelvis tilt or lumbar tilt leveling out.
Another way to measure whether one limb is longer than the other is to measure the length of each limb relative to a central point of the body. Thus, an examiner measures from a non-fixed point to a fixed point to determine the apparent leg length discrepancy. In this case, the fixed point usually is the patient's navel and the non-fixed point is either the patient's heel or ankle.
When measuring from the fixed point, this may determine whether the leg is shorter than the other, but the actual cause of the leg being shorter than the other may be because of a pelvic obliquity, meaning that the pelvic bone is unlevel and not horizontal. Accordingly, both legs may have the same length as measured with respect to the iliac crest, but this would not be determined by using the fixed point or navel of the patient. Further, it is difficult to determine how much tilt exists across the iliac crest using conventional means.
X-ray incorporating the full pelvis and lower extremities may also be taken and then measured. X-rays subject the patient to radiation exposure as well as to the inconvenience of visiting the radiology center and undergoing the radiological procedure.
Accordingly, there is a need for an apparatus and method for measuring the proper length of a patient's limb, such as a leg, that factors in the lumbar tilt without including false measurements typically caused by subjective observations utilized in the prior art.